The specific goal of this research is the elucidation of the pathways of glycolate and glyoxalate metabolism in liver mitochondria and peroxisomes. These short term objectives are part of a program to identify factors that control the endogenous hepatic biosynthesis of oxalic acid. Glyoxalate labelled with 13C will be incubated with purified 2- ketoglutarate dehydrogenase and the products identified by NMR- spectroscopy. Similar experiments with 13C labelled substrates including glycolate, glyoxalate and 2-ketoglutarate will be performed with intact mitochondria. By monitoring the results with NMR spectroscopy, the identity of the immediate metabolic products and the metabolic fates of the condensation products of glyoxalate will be learned. Parallel experiments performed with 14C substrates will allow the evaluation of the effects of glycolate, glyoxalate and their metabolic products on mitochondrial metabolism and the effect of various substrates and incubation conditions on glycolate and glyoxalate metabolism. 13C Labelled glycolate and glyoxalate will be incubated with the peroxisomal fraction from liver. The products will be identified by NMR spectroscopy and quantified by parallel experiments using 14C-substrates. Here also, the factors that influence the formation of the various metabolic products will be explored.